It seems the netx.jar was removed in the latest version of icedtea-netxin unstable. The version in testing still works. Could you try thefollowing and report back if it works for you?Edit /usr/bin/sweethome3d and replace the linefind_jars /usr/share/icedtea-web/netx.jarwithfind_jars /usr/share/icedtea-web/javaws.jarDoes the game start again?